Merit Cudkowicz has been working on ALS for three decades. She knew who she wanted to tell as soon as she was able to discuss the breakthrough findings publicly.

“The first person I called was the husband of my very first [ALS] patient, when I was a fellow,” she said.

His wife had been diagnosed at 44 with the fast-moving A4V variant of the deadly disease. The intervening decades were a period marked by “a lot of trials, a lot of progress, but nothing really earth-shattering, right?” Cudkowicz said.

Until now.

A paper published this winter in JAMA Neurology found that a new drug, called tofersen, can radically slow and even reverse the course of the disease in a small subset of patients with a rare genetic variant.